Hee! I made Heroes Sims too, the Petrelli family (Peter, Nathan, Claire) and Mohinder and Sylar. Mine don't look a lot alike either ;) A way to do that is to create skins by projecting a photograph onto the skintone (I personally don't like how that looks - photorealistic sims scare me ^_^;;)

this is my Sylar-sim (http://i16.photobucket.com/albums/b22/yaoi_icontest/sims/sylar04.jpg), looking darkly at my Mohinder-sim. I went for the Zane-look :p (my Mohinder and Sylar recently had a baby... I feared for how the poor thing would end up looking, but he's GORGEOUS. I was shocked :p)